[Bob B.]

You could make a pretty good case that GMC intended the V-6 to be either gas or diesel almost from the beginning. From what I understand, the V-6 family was intended to replace all the GMC built straight 6 gasoline engines along with the Pontiac and Oldsmobile V-8's that GMC was using the late 50's. Concurrently there was another program to develop a 4 cycle mid-range diesel engine, and at some point it merged into the V-6 program. The result was the Toro-Flow. Very true the Toro-Flow had problems (particularly the early versions) but so did most of the other big bore, short stroke mid-range diesels of the era, like the Cummins V-6 and '555' V-8. We could have a pretty good discussion about what was wrong (and right!) with the Toro-Flow. I may have mentioned in the past that I volunteer at a railroad museum, and we have a functioning D478 Toro-Flow in a bus. I'll post more about my experiences and what I have learned over the years about these oddball diesels in the next few days.